1. Field of the Invention
The invention concerns a device for the sterilization of liquids by means of ultraviolet rays whereby a low-pressure high-current mercury-vapor lamp (UV-lamp) is used as the radiation source and which is provided with a cecum-shaped piece of tubing (cecum) arranged at the discharge tube such that, for the cooling of the UV-lamp, an air flow circulates through the device which is led in such a manner that the air heated at the discharge tube passes the electrode bulbs of the UV-lamp and reaches the outer wall of the piping through which the liquid flows that is to be sterilized. Moreover, the air cooled at the outer wall of the piping again returns to the UV-lamp and has a temperature which is lower than the operating temperature of the cecum such that, initially, at least part of the air reaches the cecum and the given temperature of the cecum is controlled by a heating device.
2. Description of the Prior Art
A similar device was already proposed in the Swiss Patent Application No. 6207/78 corresponding to U.S. Pat. No. 4,250,391. In the case of this device, the air flow for the cooling of the UV-lamp passes through the space around the cecum to the heated discharge tube arranged in a quartz protection tube as shown in FIG. 1.
In this instance, the circulating speed of the air flow, the temperature of the liquid to be sterilized and the heating device determine the temperature of that portion of the air flow destined for cooling of the UV-lamp. In the case of cold liquids, it might become necessary to supply a high quantity of energy to the cooled air by means of the heating device.